Problem: Expand and combine like terms. $(8n^2+3n^7)(8n^2-3n^7)=$
Answer: We can expand this expression like any product of two binomials. However, this expression has a special form that makes it easier to expand. This is the "difference of squares" form (where $P$ and $Q$ can be any monomial): $(P+Q)(P-Q)=P^2-Q^2$ $\begin{aligned} &\phantom{=}(8n^2+3n^7)(8n^2-3n^7) \\\\ &=\left(8n^2\right)^2-\left(3n^7\right)^2 \\\\ &=64n^{4}-9n^{14} \end{aligned}$